unable to update z10

hiii... i have z10.... my phone software version is10.1.0.273. and it show a notification for software update version 10.2.1.2977. but i have tried a number of times to update but i am unable to do that. it downloads the update files and while installing after 90% it gives some error "software update was interrupted". i also tried to update via bb link but show shows a different update version but after 8% it gives error to check internet connection. guys ... plz help me to update my phone

How stable is your internet access? and WiFI? If you never had any issue with your device until now, I would first try to do the update from another location, friends home, work.
Then try a hard reset before doing the update, hold both vol up/dn until you see the boot screen, then try again.
Failing that, you may have to just bit the bullet and do a wipe/restore. Copy all your images/vids/music/docs
All you want to keep to your PC, then run a backup of your device using BBLink (this way you get to keep your app data) and save it. Make sure you check the box for app data!
Then do a wipe and reload, and then you should be good to go.

If you are having issues OTA the best way is via BlackBerry Link
First make sure you have the most up to date version of Link
Reboot the PC
And try again, it's important to make sure you have a stable Internet connection